|Magnetohydrodynamic simulations of turbulent magnetic reconnection|
|Fan QL(范全林); Feng XS(冯学尚); Xiang ZQ(向长青); 北京8701信箱
|Source Publication||Magnetohydrodynamic simulations of turbulent magnetic reconnection
|Abstract||Turbulent reconnection process in a one-dimensional current sheet is investigated by means of a two-dimensional compressible one-fluid magnetohydrodynamic simulation with spatially uniform, fixed resistivity. Turbulence is set up by adding to the sheet pinch small but finite level of broadband random-phased magnetic field components. To clarify the nonlinear spatial-temporal nature of the turbulent reconnection process the reconnection system is treated as an unforced initial value problem without any anomalous resistivity model adopted. Numerical results demonstrate the duality of turbulent reconnection, i.e., a transition from Sweet-Parker-like slow reconnection to Petschek-like fast reconnection in its nonlinear evolutionary process. The initial slow reconnection phase is characterized by many independent microreconnection events confined within the sheet region and a global reconnection rate mainly dependent on the initially added turbulence and insensitive to variations of the plasma beta and resistivity. The formation and amplification of the major plasmoid leads the following reconnection process to a rapid reconnection stage with a fast reconnection rate of the order of 0.1 or even larger, drastically changing the topology of the global magnetic field. That is, the presence of magnetohydrodynamic turbulence in large-scale current sheets can raise the reconnection rate from small values on the order of the Sweet-Parker rate to high values on the order of the Petscheck rate through triggering an evolution toward fast magnetic reconnection. Meanwhile, the backward coupling between the small- and large-scale magnetic field dynamics has been properly represented through the present high resolution simulation. The undriven turbulent reconnection model established here expresses a solid numerical basis for the previous schematic two-step magnetic reconnection models and a possible explanation of two-stage energy release process of solar explosives.|
Fan QL,Feng XS,Xiang ZQ,et al. Magnetohydrodynamic simulations of turbulent magnetic reconnection[J]. Magnetohydrodynamic simulations of turbulent magnetic reconnection,2004,11(12):5605-5614.
范全林,冯学尚,向长青,&北京8701信箱.(2004).Magnetohydrodynamic simulations of turbulent magnetic reconnection.Magnetohydrodynamic simulations of turbulent magnetic reconnection,11(12),5605-5614.
范全林,et al."Magnetohydrodynamic simulations of turbulent magnetic reconnection".Magnetohydrodynamic simulations of turbulent magnetic reconnection 11.12(2004):5605-5614.
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